I'm looking for not-so-expensive ways to track occupants inside a home. I have been for years. I have looked at RFID with mid-range readers, motion detection, IR beam-break detectors, etc. They all fall short for me though. I want to know exactly who is in what room and when so that I can actually tailor the home environment to them. I thought bluetooth could be useful for this because BT devices are cheap. I could put readers around the house and measure RF power to estimate a position.
Recently I noticed that the concept of beacons was becoming popular in retail. I started exploring this as an option for my home. What I found is that the typical use case is for the beacons to be placed in specific locations and then the user launches a phone app to determine where in space the phone is based on those beacons. Retailers can then target messages, ads, or customer service to them. I wanted the system to work in reverse.
I finally found a project where someone has created a proof of concept where the user is the Bluetooth Beacon and there are static receivers (Raspberry PIs) located in the home. The receivers can then transmit information when the beacon (ie. Occupant) comes into the room. http://stackoverflow.com/questions/21733228/can-raspberrypi-with-ble-dongle-detect-ibeacons
I hope to get to this sometime soon.